Method and apparatus for rapidly cooling a gem

ABSTRACT

A cooling apparatus includes a container configured to contain a coolant within a space. The apparatus further includes a cooling block positioned substantially within the space and having a high heat capacity such that the space not occupied by the cooling block is filled with a coolant to a level at or below the top of the cooling block, and a placement structure having high thermal conductivity positioned on top of the cooling block and outside of the space. A method for cooling an object is also provided, which includes inserting a coolant into a container configured to contain the coolant within a space, and placing the object on a placement structure outside the space. For this method, the placement structure has a high thermal conductivity and is coupled to a cooling block, the cooling block having a high heat capacity and positioned substantially within the space.

TECHNICAL FIELD

The present invention is directed generally towards cooling an object,and more specifically towards a method and apparatus for rapidly coolinga gem so as to facilitate spectral analysis.

BACKGROUND OF THE TECHNOLOGY

It is often desirable to analyze properties of an object that has beencooled to very low temperatures, such as cryogenic temperatures, forexample temperatures close to that of liquid nitrogen. When analyzing agem, for example, it is often desirable to perform a spectral analysisof the gem at cryogenic temperatures to obtain information about thecomposition of the gem. Performing a spectral analysis on a gem cooledto such temperatures is particularly useful, for example, in determiningthe color origin of diamonds which may have been subjected to varioustreatments such as irradiation, as in a nuclear reactor or by anelectron beam, or annealing, and for identifying diamonds treated underhigh-pressure and high-temperature (HPHT).

Currently available cooling apparatuses exhibit a number ofdisadvantages. For example, some currently available cooling apparatusesrequire a test sample to be cooled for approximately 20-30 minutesbefore a spectral analysis could be performed. Such a prolonged coolingperiod severely limits production capacity when a large number of gemsneed to be analyzed. Other apparatus employ direct immersion of thegemstone in the cooling medium which may result in undesirableinteraction between the cooling medium and spectral information ofinterest. Still other cooling arrangements have employed a cylindricalcopper block of approximately 2 inches in diameter, 1.8 inches inheight, and having a 0.16 inch diameter bore along its axis, and whichhas been cooled to a desired temperature and removed from the coolingenvironment prior to placement of the object to be cooled in the 0.16inch diameter bore.

Another disadvantage of some of the currently available coolingapparatuses is that they are bulky and complex. Some of theseapparatuses, for example, require the test sample to be placed within ashell that is submerged in liquid nitrogen. Because of condensation thatmay occur within the shell, however, such apparatuses require amechanism to infuse moisture-free gas into the enclosed internal chamberoccupied by the test sample. As such, in addition to the extra timerequired to infuse gas into the shell, these apparatuses add additionalcosts to the analysis task, and because of their complexity are moreprone to mechanical failure.

Accordingly, there is a need for a method and apparatus for rapidlycooling gems in an efficient and cost effective manner. Morespecifically, there is a need for a method and apparatus for coolinggems which does not require a closed environment, or infusion ofmoisture-free gas, and which allows for a rapid cool down and analysisof a large number of gems.

SUMMARY OF THE INVENTION

The present invention addresses the aforementioned problems by providingan improved method and apparatus for rapidly cooling gems in connectionwith analyzing the gems.

An embodiment of the present invention provides a cooling apparatuswhich includes a container having walls, such that the container isconfigured to contain a coolant within a space enclosed by the walls.The apparatus further includes a cooling block positioned substantiallywithin the space and having a high heat capacity. The portion of thespace not occupied by the cooling block is filled with a coolant to alevel at or below the top of the cooling block. Such an embodiment alsoincludes a placement structure having a high thermal conductivitypositioned on top of the cooling block and outside of the coolant-filledspace.

In another embodiment a cooling apparatus is provided including acontainer having an open end and a cooling block positioned within thecontainer. For this embodiment, the cooling block has a high heatcapacity, and a space between the cooling block and walls of the coolingapparatus is filled with a coolant to a level at or below the top of thecooling block. A placement structure having a high thermal conductivityis also provided, which is positioned outside of the coolant-filledspace and in contact with a face of the cooling block that is accessibleat the open end of the container.

In another embodiment of the present invention, a method for cooling anobject is also provided, which includes inserting a coolant into acontainer configured to contain the coolant within a space and placingthe object on a placement structure outside the space. Within suchembodiment, the placement structure has a high thermal conductivity andis coupled to a cooling block. Also within this embodiment, the coolingblock has a high heat capacity and is positioned substantially withinthe space.

In a further embodiment, a cooling apparatus is provided which includesa container configured to contain a coolant within a space. Within suchembodiment, a cooling block having a high heat capacity is positionedsubstantially within the space such that the space not occupied by thecooling block is filled with a coolant to a level at or below the top ofthe cooling block. The apparatus also includes a placement structurehaving a high thermal conductivity, such that the placement structure iscoupled to the cooling block and isolated from the space.

In another embodiment of the present invention, a method for cooling anobject is provided, which includes pouring a coolant into a spacebounded by a container and positioning the object on a placementstructure having a high thermal conductivity. Within such embodiment,the placement structure is coupled to a cooling block having a high heatcapacity and positioned substantially within the space, such that theobject is isolated from the space.

Through the use of a device and method in accordance with the presentinvention spectral patterns have been obtained which much moreaccurately reflect the color of analyzed samples.

As will be appreciated upon consideration of the following detaileddescription of the invention and accompanying drawings, there are manyadvantages and features of the present invention, which in turn lead tomany new and useful applications of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary cooling apparatus having low walls according toan embodiment of the invention.

FIG. 2A is an exemplary cooling apparatus having high walls, wherein thespectral analysis optical path line is routed to enter the enclosedspace through the open end of the container, according to an embodimentof the invention.

FIG. 2B is an exemplary cooling apparatus having high walls, wherein thespectral analysis optical path line is routed through a very narrow slitin the high walls that is dimensioned to accommodate an optical fiber,according to another embodiment of the invention.

FIG. 3A is an exemplary graph comparing the spectral analysis of a 0.16carat gem obtained using an apparatus of the prior art versus anapparatus according to an embodiment of the invention.

FIG. 3B is an exemplary graph comparing the spectral analysis of a 0.11carat gem obtained using an apparatus of the prior art versus anapparatus according to an embodiment of the invention.

FIG. 3C is an exemplary graph comparing the spectral analysis of a 0.14carat gem obtained using an apparatus of the prior art versus anapparatus according to an embodiment of the invention.

FIG. 3D is an exemplary graph comparing an enlargement of a portion ofthe spectral analysis of a 0.10 carat gem of FIG. 3C obtained using anapparatus of the prior art versus an apparatus according to anembodiment of the invention.

FIG. 3E is an exemplary graph comparing the spectral analysis of a 0.50carat gem obtained at different cooling times using an apparatusaccording to an embodiment of the invention.

FIG. 3F is an exemplary graph comparing the spectral analysis of a 2.5carat gem obtained using an apparatus of the prior art versus anapparatus according to an embodiment of the invention.

FIG. 4 is a schematic of a system employing an embodiment of a coolingapparatus according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed towards providing an improved methodand apparatus for cooling objects by the use of a coolant. In aparticular application, the present invention provides an efficient opento the air solution for rapid cooling of gems to cryogenic temperatures,for use in a system that perform spectral analysis of gems at suchtemperatures. Moreover, for such applications, a significant improvementfrom prior art methods and apparatuses is provided since the presentinvention cools gems much faster and does not require complex mechanismsthat infuse moisture-free gas. Such an improvement is particularlyuseful when a large number of gems need to be individually analyzed.

In FIG. 1, an exemplary cooling apparatus according to an embodiment ofthe invention is provided. As illustrated, a cooling apparatus 100includes a container 110, a cooling block 120, and a placement structure130. In a preferred embodiment, placement structure 130 is positioned ontop of cooling block 120, and cooling block 120 is positioned in thecenter of container 110, as shown.

In use, cooling apparatus 100 may be used in conjunction with anintegrating sphere 400 to analyze the spectral properties of an object300 cooled to a desired temperature. Within such embodiment, the spacebetween cooling block 120 and container 110 is preferably filled with acoolant 200 (e.g., liquid nitrogen) to a height just below the top ofcooling block 120, as shown. By selecting a cooling block 120 with asufficiently high heat capacity, and by selecting a placement structure130 with a sufficiently high thermal conductivity, object 300 is quicklyand effectively cooled to the desired temperature. Preferably, thesample is first cooled down to the coolant (e.g. liquid nitrogen)temperature quickly by direct immersion in coolant, then transferred tothe block. In this way, the sample is cooled down even faster, and alsoproperly maintained. Once object 300 is cooled, integrating sphere 400may then be positioned over object 300 and about placement structure 130as shown. Object 300 may then be illuminated via illumination feed line410, and spectral response information may then be collected viaspectral optical path line 420.

In the discussion that follows, the structural dimensions of variousaspects of the present invention are discussed, and dimensions for aparticular embodiment are given. However, it should be noted that suchdimensions are provided solely as an example of particular embodimentsand are not intended to limit the scope and spirit of the invention.Furthermore, it will be apparent to one skilled in the art upon readingthese descriptions that other materials, dimensions, configurations andarrangements can be used to implement the teachings of this applicationand the concepts of the present invention.

As shown in FIG. 1, the illustrated embodiment includes an insulationcontainer 110 preferably having a rectangular cross section. A varietyof container shapes may be used, including cylindrical and cubic shapedcontainers. In a prototype of cooling apparatus 100, insulationcontainer 110 was made of Styrofoam® material, in which the walls had aheight of approximately 20 cm uniform thickness of approximately 5 mmand the dimensions of the base were approximately 20 cm. For theparticular embodiment of FIG. 1, it should be appreciated that the sidewalls were configured to have a uniform height substantially even withthe height of cooling block 120, as shown.

Meanwhile, cooling block 120 fits substantially within insulationcontainer 110, as shown, where it firmly rests either due to its weightalone or from being affixed to the base of insulation container 110. Ina preferred embodiment, cooling block 120 has a cylindrical shape andhas a high heat capacity, which provides a “heat sink” so that object300 is cooled to a temperature at or about the temperature of coolingblock 120. Cooling block 120 is preferably made from a material and hasa mass such that the heat energy required to increase the temperature ofcooling block 120 by a certain temperature interval is large, so thatthe object 300 being evaluated quickly reaches a temperature at or nearthe temperature of cooling block 120. In a preferred use of theembodiments of the cooling apparatus, a sample is first pre-cooled incoolant located either external to or within the container 110, and thenplaced upon the cooling block 120, which permits a very low temperatureto be maintained by the block. Materials which have high heat capacitysuitable for use in the invention include, for example, copper, iron,indium. In a prototype, cooling block 120 was made of copper having aheight of approximately 70 mm and a diameter of approximately 63.5 mm.

Placement structure 130 is preferably positioned on top surface 122 ofcooling block 120, as shown for example in FIGS. 2A and 2B, where it ispreferably positioned within a relief 132 formed within the top surface122. Placement structure 130 may be friction-fit into relief 132,affixed to top surface 122 by way of a suitable thermally conductiveadhesive, or attached to stop surface 122 through other suitablemechanisms which promote thermal conduction between placement structure130 and cooling block 120. In a preferred embodiment, placementstructure 130 is disc-shaped and has a high thermal conductivity so asto facilitate an efficient transfer of energy from object 300 to coolingblock 120. Preferably, materials having thermal conductivity at or abovethat of high purity alumina or SPECTRALON® polymer material may be usedfor placement structure 130. For some embodiments, the desiredconductivity may be achieved by constructing placement structure 130 outof aluminum. For particular applications, however, it should beappreciated that placement structure 130 may need to exhibit propertiesnot necessarily provided by aluminum. For spectral analysis, forexample, a placement structure 130 that provide's a background forobject 300 that minimizes false readings, may be used. Also, theplacement structure may be configured to promote coupling to integratingsphere 400. For such embodiments, placement structure 130 preferablyutilizes materials with high thermal conductivity and which provide a“white” background, such as any of a plurality of materials includingTEFLON®, white ceramic, boron silicate, and aluminum oxide. Placementstructure 130 may be made entirely of such materials or such materialsmay be used to line the surface of placement structure 130. Placementstructure 130 may thus be designed to provide both high thermalconductivity and a background having a desired absorptioncharacteristics. In a preferred embodiment, placement structure 130 maybe a disc of TEFLON® polymer material having a thickness ofapproximately 0.1 inch and a diameter of approximately 1.0 inch.

In a preferred embodiment, it should be appreciated that coolingapparatus 100 may be used for spectral analysis in conjunction with anyof a plurality of commercially available integrating spheres 400. In aprototype, an integrating sphere 400 manufactured by Avantes BV, ofEerbeek, Netherlands, was used, which included an illumination feed line410 and a spectral optical path line 420, as shown. During use,integrating sphere 400 is coupled to placement structure 130 so as tosubstantially cover object 300. Illumination feed line 410 provideslight to the inner portion of integrating sphere 400 so as to provideillumination for object 300. Spectral optical path line 420 provides anoptical path for communicating the resulting spectral response of object300 to analysis equipment such as a spectrometer. The above arrangementfacilitates spectral analysis of object 300 which has been cooled bycooling apparatus 100.

In a preferred embodiment of the invention, as illustrated in FIGS. 2Aand 2B, the walls of container 112 (and container 114) are designed toextend to a height substantially higher than the height of cooling block120, and thereby to extend to a height substantially higher than the topof object 300 when placed on placement structure 130, as shown. In aprototype, the walls were designed to extend approximately 2 incheshigher than the height of object 300. By implementing such a design,when coolant 200 is in liquid form, such as dry liquid nitrogen,vaporized gas emanating from coolant 200 will fill the space abovecoolant 200 and displace the ambient gases from around object 300. Thevaporized gas from coolant 200 may flow over the heightened walls ofcontainers 112 or 114, for example, thus filling the interior spaceabove cooling block 120 and coolant 200 with the vaporized gas. As aresult, the vaporized gas is present above the top of cooling block 120and serves as a dry atmosphere to prevent condensation on object 300.

When such an embodiment is used in conjunction with integrating sphere400, it should be further noted that spectral optical path line 420 mayeither be routed along the interior and over the top of the walls ofcontainer 112, as shown in FIG. 2A, or through a wall of container 114,as shown in FIG. 2B. Preferably, for the configuration of FIG. 2B, anarrow slit, of about 5 mm in width, is provided for passage of thefiber through the container wall.

The present invention has provided a useful tool for performing spectralanalysis on gems, which require the gems to be cooled to a particulartemperature. Namely, relative to prior art apparatuses, the presentinvention provides a cooling apparatus which cools gems much faster andyields spectrums of much higher quality. To better illustrate theutility of the present invention, FIGS. 3A-3C provide chartsillustrating a comparison of plots of spectral responses of gemsweighing 0.16, 0.11, and 0.14 carats obtained using an apparatus of theprior art versus an apparatus according to an embodiment of theinvention. In each of these charts, four plots are provided. One plotshows the spectrum obtained, plotted at an interval step of 0.10nanometers, using a prior art apparatus in which the gem had been cooledfor approximately twenty minutes. Using the prior apparatus, it takesabout 20 minutes to get the sample cooled down and about another 20minutes to collect a spectrum. The prior art apparatus employed a Unicamspectrometer with cryostat, provided by Thermo Elemental, of Franklin,Mass. The other three plots were obtained using embodiments of thepresent invention for spectral accumulation of the gem at each of ten,twenty, and twenty-two seconds, and plotted at interval steps of 0.47,0.47, and 0.33 nanometers, respectively. A system by which the spectralinformation was analyzed and plotted to yield these plots is describedin further detail in co-pending U.S. patent application Ser. No. ______,entitled “FAST UV-VIS-NIR ABSORPTION SPECTROMETER SYSTEM AND METHOD”,attorney-docket number 353397-165957, filed even-date herewith, andincorporated by reference herein in its entirety (“Gem Spectral AnalysisSystem Application”). As illustrated, in addition to cooling the gemsmuch more quickly than the prior art apparatus, the present inventionprovides a relatively higher quality spectrum that includes less noisefor a wavelength region between 450 and 850 nanometers. In FIGS. 3A-3C,for example, the plotted response in the wavelength region between 700and 750 nanometers has been circled to highlight the higher quality ofthe spectrums obtained, over a substantially shorter amount of time,using the present invention compared to that obtained though the priorart arrangement.

In FIG. 3D, an exemplary graph comparing the spectral response, over a580 nm to 610 nm range, of a 0.10 carat gem obtained using an apparatusof the prior art versus an apparatus according to an embodiment of theinvention is provided. For this particular graph, spectrum responsesplotted at interval steps of 0.47 nanometers of the gem cooled by thepresent invention for each with spectral accumulation time of ten andtwenty seconds are compared to a spectrum taken at an interval step of0.10 nanometers of the same gem cooled by a prior art apparatus, whichrequired a cooling time of approximately twenty minutes and anothertwenty minutes for spectral acquisition. As illustrated, FIG. 3D showshow quickly the spectrum obtained using the present invention “sharpensup” relative to the spectrum obtained by the prior art apparatus. FIG.3D thus illustrates how rapidly spectral information can be obtainedwith reduced noise characteristics.

In FIG. 3E, an exemplary graph comparing the spectral analysis of a 0.50carat gem obtained at different spectral accumulation times using anapparatus according to an embodiment of the invention is provided. Inparticular, three plots are provided which represent the spectraproduced with accumulation time of ten, twenty, and twenty-two seconds,and at interval steps of 0.47, 0.47, and 0.33 nanometers, respectively.As illustrated, the spectrum produced with accumulation time oftwenty-two seconds shows a relatively higher quality spectrum in termsof reduced noise than the spectrums produced with accumulation time often and twenty seconds. However, it is also to be noted that even afteronly 10 seconds of data accumulation, the spectrum peaks and generalspectral characteristics are already apparent. In the wavelength regionbetween 350-400 nanometers, for example, the plot representing thetwenty-two second of data accumulation period exhibits much less noisethan the plots representing the ten and twenty second accumulationperiods. As illustrated, the peaks, while present in all of the plots,are also relatively more defined in the plot for the twenty-two secondaccumulation period compared to the plots for the ten and twenty secondaccumulation periods (see e.g., the peaks at approximately 503, 595, and741 nanometers).

In FIG. 3F, an exemplary graph comparing the spectral response of a 2.5carat gem obtained using an apparatus of the prior art versus anapparatus according to an embodiment of the invention is provided. Forthis particular graph, the spectrum (plotted at an interval step of 0.47nanometers) for the gem collected by the present invention for twentyseconds, is compared to a spectrum (plotted at an interval step of 0.10nanometers) of the same gem cooled by a prior art apparatus, whichrequired a cooling time of approximately twenty minutes and dataacquisition of another twenty minutes. As illustrated, not only are theplots relatively similar for the wavelength region below 450 nanometers,but the quality of the spectrum for wavelengths greater than 450nanometers obtained using the present invention is markedly cleaner andhigher sensitivity than the spectrum obtained using the prior artapparatus. Namely, through the use of the present invention a spectrumwas obtained with much less noise, much more defined peaks, andsubstantially more quickly than that obtained using the prior artarrangement (see e.g., the peaks at approximately 503, 595, and 741nanometers).

Referring to FIG. 4, the components of an embodiment of a gem spectralanalysis system 600 which incorporates the cooling structure of thepresent invention will now be briefly described. Such a gem spectralanalysis system may be that which is described in the “Gem SpectralAnalysis System Application” referenced hereinabove.

In gem spectral analysis system 600, gem cooling apparatus 100 isprovided for cooling an object 300 being evaluated to a desiredtemperature. An integrating sphere unit 400 is placed over an object300. Object 300 is cooled to the desired temperature by coolingapparatus 100. Although reference is made to gem cooling apparatus 100,it is to be understood that the embodiments of gem cooling apparatus 102and 104 may also be used in gem spectral analysis system 600.

Integrating sphere unit 400 illuminates the object 300 withelectromagnetic radiation, which may be light of selected wavelengths,and then gathers the spectral response of the illuminated gem.Integrating sphere unit 400 may be implemented using model no.AvaSphere-50, manufactured by Avantes BV of Eerbeek, Netherlands. Theselected wavelengths of light for illuminating object 300 may beprovided by a light source 412, such as a tungsten halogen light sourcemodel AVALight-Hal-S, manufactured by Avantes BV of RB Eerbeek,Netherlands. Optical cable 410 may be used to route light from lightsource 412 to the integrating sphere unit 400. The gathered spectralresponse from integrating sphere unit 400 may be routed over opticalcable 420 to a high resolution spectrometer unit 422, such as model no.HR4000, manufactured by Ocean Optics of Dunedin, Fla. The highresolution spectrometer unit 422 measures the amount of light as afunction of wavelength in the gathered spectral response and transformsthe measurements into digital information. The gathered spectralresponse data, in digital form, is then provided for further processingby computer 500. Cable 424 may be used to couple spectrometer unit 422to computer 500 to provide a path for the spectral response data.

Computer 500 preferably includes software applications by which thespectral response information from spectrometer unit 422 may be furtherprocessed. Such processing may be for purposes of displaying an image ona computer screen of a depiction of the spectral response as a functionof wavelength, as shown in FIG. 4, for detecting and analyzingcharacteristics of the spectral response, for extracting specified datafrom the spectral response information, and the like. Although a laptopcomputer is depicted in FIG. 4, it is to be understood that othercomputing or processing devices such as a desktop computer or dedicatedcontroller unit, and the like, may be used, with or without an imagedisplay, within the spirit of the present invention.

The present invention has been described above with reference to severaldifferent embodiments. However, those skilled in the art will recognizethat changes and modifications may be made in the above describedembodiments without departing from the scope and spirit of theinvention. Furthermore, while the present invention has been describedin connection with a specific processing flow, those skilled in the artwill recognize that a large amount of variation in configuring theprocessing tasks and in sequencing the processing tasks may be directedto accomplishing substantially the same functions as are describedherein. These and other changes and modifications which are obvious tothose skilled in the art in view of what has been described herein areintended to be included within the scope of the present invention.

1. A cooling apparatus comprising: a container having walls, wherein thecontainer is configured to contain a coolant within a space enclosed bythe walls; a cooling block positioned substantially within the space,wherein the cooling block has a high heat capacity, and wherein aportion of the space not occupied by the cooling block is filled with acoolant to a level at or below a top face of the cooling block; and aplacement structure positioned on top of the cooling block and outsideof the coolant-filled space, wherein the placement structure has a highthermal conductivity, and further wherein the container walls have aheight and the cooling block has a height, and the height of thecontainer walls are substantially the same as the height of the coolingblock.
 2. The cooling apparatus of claim 1, wherein a perimeter formedby the walls is circular.
 3. The cooling apparatus of claim 1, whereinthe placement structure comprises TEFLON® or SPECTRALON®.
 4. A coolingapparatus comprising: a container having an open end defined by aperimeter; a cooling block positioned within the container, wherein thecooling block has a high heat capacity, and wherein a space between thecooling block and walls of the cooling apparatus is filled with acoolant to a level at or below a top face of the cooling block, andfurther wherein the perimeter has a height and the cooling block has aheight, and the height of the perimeter is substantially the same as theheight of the cooling block; and a placement structure positionedoutside of the coolant-filled space and in contact with the top face ofthe cooling block that is accessible at the open end of the container,wherein the placement structure has a high thermal conductivity.
 5. Thecooling apparatus of claim 4, wherein the placement structure isconfigured to engage with an integrating sphere.
 6. The coolingapparatus of claim 4, wherein the perimeter is square:
 7. A coolingapparatus comprising: a container configured to contain a coolant withina space; a cooling block positioned substantially within the space,wherein the cooling block has a high heat capacity, and wherein aportion of the space not occupied by the cooling block is filled with acoolant to a level at or below a top face of the cooling block, andfurther wherein the container has a height and the cooling block has aheight, and the height of the container is substantially the same as theheight of the cooling block; and a placement structure coupled to thecooling block and external to the space filled with the coolant, whereinthe placement structure has a high thermal conductivity.
 8. The coolingapparatus of claim 7, wherein the container is shaped to accommodate anoptical path line of an integrating sphere.
 9. The cooling apparatus ofclaim 7, wherein the placement structure is configured to engage with anintegrating sphere.
 10. A method for cooling an object comprising:inserting a coolant into a container configured to contain the coolantwithin a coolant-space; and placing the object on a placement structureoutside the coolant-space, wherein the placement structure has a highthermal conductivity and is coupled to a cooling block, and wherein thecooling block has a high heat capacity and is positioned substantiallywithin the coolant-space, and further wherein the container has a heightsubstantially the same as a height of the cooling block, and the coolantis inserted to a height lower than a height of the placement structure.11. The method of claim 10 further comprising engaging an integratingsphere with the placement structure.
 12. A method for cooling an objectcomprising: pouring a coolant into a space bounded by a container; andpositioning the object on a placement structure having a high thermalconductivity, wherein the placement structure is coupled to a coolingblock having a high heat capacity and positioned substantially withinthe space, and wherein the object is positioned apart from the spaceoccupied by the coolant, and further wherein the container has a heightsubstantially the same as a height of the cooling block, and furthercomprising pouring the coolant to a height lower than a height of theplacement structure.
 13. The method of claim 12 further comprisingengaging an integrating sphere with the placement structure.
 14. Acooling apparatus comprising: a container having walls, wherein thecontainer is configured to contain a coolant within a space enclosed bythe walls; a cooling block positioned substantially within the space,wherein the cooling block has a high heat capacity, and wherein aportion of the space not occupied by the cooling block is filled with acoolant to a level at or below a top face of the cooling block, andfurther wherein the container walls have a height substantially the sameas a height of the cooling block; and a placement structure positionedon top of the cooling block and outside of the coolant-filled space,wherein the placement structure has a high thermal conductivity andcomprises aluminum.
 15. A method for cooling an object comprising:inserting a coolant into a container configured to contain the coolantwithin a coolant-space; and placing the object on a placement structureoutside the coolant-space, wherein the placement structure has a highthermal conductivity and comprises aluminum and is coupled to a coolingblock, and wherein the cooling block has a high heat capacity and ispositioned substantially within the coolant-space, and the coolant isinserted to a height lower than a height of the placement structure, andfurther wherein the container has a height substantially the same as aheight of the cooling block.